Law enforcement officials in Moab are bracing for the arrival of hundreds of motorcycle riders who are part of one of the country's most visible biker gangs.

The international Bandidos Motorcycle Club is expected to arrive in town on Thursday for a weekend-long "annual conference." Moab Police Chief Michael Navarre said law enforcement officials expect 500 to 800 riders.

Because of the group's reputation, Moab officials asked for emergency funding from the Utah Commission on Criminal and Juvenile Justice to pay for an increased law-enforcement presence during the rally. The commission this week approved $55,000 to help pay overtime, lodging and per-diem expenses for law enforcement agencies from around Utah to assist the 14-person Moab Police Department during the event.

Local officials declined to say how many extra officers they plan to have on duty for the event.

"We're being pretty tight-lipped about the entire operation because we don't really know what to expect," said Moab Mayor David Sakrison.

City officials learned about the event about four months ago and quickly begin discussing how it should be handled.

Utah police have contacted Arizona authorities to discuss how they managed a 2007 gathering in Flagstaff in which there were no major problems.

The Bandidos have about 2,500 members in 13 countries, according to federal estimates.

Small groups can be found in Utah, particularly in Tooele County, said Bruce Champagne, president of the Utah Gang Investigators Association.

"They would have you believe they're clubs, but they're not. They're involved in criminal enterprise," said Champagne, noting the gang can be "incredibly violent."

"They've been actively recruiting, and their presence has grown in Utah over the last few years," he said.

During the upcoming rally, law enforcement officers will have to strike a balance between keeping an eye on the gathering and not intruding on the group's right to meet, according to Al Valdez, a professor at the University of California-Irvine and a former gang investigator.

The primary issue will be whether a rival game shows up to stir up trouble, he said.

"A larger police presence deters rivals from showing up," said Valdez, who spoke at the Utah Gang Conference in April and has authored several text books on gangs.

"It's not going to be a gestapo like-presence. They'll be in the shadows," he said of police.